/* vi: set sw=4 ts=4: */
/*
 * Packet ops
 *
 * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */

#include "udhcp/common.h"
#include "udhcp/dhcpd.h"

void ICACHE_FLASH_ATTR udhcp_init_header(struct dhcp_packet *packet, char type)
{
	memset(packet, 0, sizeof(*packet));
	packet->op = BOOTREQUEST; /* if client to a server */
	switch (type) {
	case DHCPOFFER:
	case DHCPACK:
	case DHCPNAK:
		packet->op = BOOTREPLY; /* if server to client */
		break;
	}
	packet->htype = 1; /* ethernet */
	packet->hlen = 6;
	packet->cookie = htonl(DHCP_MAGIC);
	if (DHCP_END != 0)
		packet->options[0] = DHCP_END;
	udhcp_add_simple_option(packet, DHCP_MESSAGE_TYPE, type);
}

#if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 2
void udhcp_dump_packet(struct dhcp_packet *packet)
{
	char buf[sizeof(packet->chaddr)*2 + 1];

	if (dhcp_verbose < 2)
		return;

	bb_info_msg(
		//" op %x"
		//" htype %x"
		" hlen %x"
		//" hops %x"
		" xid %x"
		//" secs %x"
		//" flags %x"
		" ciaddr %x"
		" yiaddr %x"
		" siaddr %x"
		" giaddr %x"
		//" chaddr %s"
		//" sname %s"
		//" file %s"
		//" cookie %x"
		//" options %s"
		//, packet->op
		//, packet->htype
		, packet->hlen
		//, packet->hops
		, packet->xid
		//, packet->secs
		//, packet->flags
		, packet->ciaddr
		, packet->yiaddr
		, packet->siaddr_nip
		, packet->gateway_nip
		//, packet->chaddr[16]
		//, packet->sname[64]
		//, packet->file[128]
		//, packet->cookie
		//, packet->options[]
	);
	*bin2hex(buf, (void *) packet->chaddr, sizeof(packet->chaddr)) = '\0';
	bb_info_msg(" chaddr %s", buf);
}
#endif

/* Read a packet from socket fd, return -1 on read error, -2 on packet error */
int ICACHE_FLASH_ATTR udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd)
{
	int bytes;

	memset(packet, 0, sizeof(*packet));
	bytes = safe_read(fd, packet, sizeof(*packet));
	if (bytes < 0) {
		UDHCP_DEBUG("Packet read error, ignoring\n");
		return bytes; /* returns -1 */
	}

	if (//bytes < offsetof(struct dhcp_packet, options)
	 //|| packet->cookie != htonl(DHCP_MAGIC)
		packet->cookie != htonl(DHCP_MAGIC)
	) {
		UDHCP_DEBUG("Packet with bad magic, ignoring\n");
		return -2;
	}
	UDHCP_DEBUG("Received a packet\n");
	udhcp_dump_packet(packet);

	return bytes;
}

///* Construct a ip/udp header for a packet, send packet */
//int ICACHE_FLASH_ATTR udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
//		uint32_t source_nip, int source_port,
//		uint32_t dest_nip, int dest_port, const uint8_t *dest_arp,
//		int ifindex)
//{
////	struct sockaddr_ll dest_sll;
//	struct ip_udp_dhcp_packet packet;
//	unsigned padding;
//	int fd;
//	int result = -1;
//	const char *msg;
//
////	fd = socket(PF_PACKET, SOCK_DGRAM, htons(ETH_P_IP));
//	if (fd < 0) {
//		msg = "socket(%s)\n";
//		goto ret_msg;
//	}
//
////	memset(&dest_sll, 0, sizeof(dest_sll));
////	memset(&packet, 0, offsetof(struct ip_udp_dhcp_packet, data));
//	packet.data = *dhcp_pkt; /* struct copy */
//
////	dest_sll.sll_family = AF_PACKET;
////	dest_sll.sll_protocol = htons(ETH_P_IP);
////	dest_sll.sll_ifindex = ifindex;
////	dest_sll.sll_halen = 6;
////	memcpy(dest_sll.sll_addr, dest_arp, 6);
//
////	if (bind(fd, (struct sockaddr *)&dest_sll, sizeof(dest_sll)) < 0) {
////		msg = "bind(%s)";
////		goto ret_close;
////	}
//
//	/* We were sending full-sized DHCP packets (zero padded),
//	 * but some badly configured servers were seen dropping them.
//	 * Apparently they drop all DHCP packets >576 *ethernet* octets big,
//	 * whereas they may only drop packets >576 *IP* octets big
//	 * (which for typical Ethernet II means 590 octets: 6+6+2 + 576).
//	 *
//	 * In order to work with those buggy servers,
//	 * we truncate packets after end option byte.
//	 *
//	 * However, RFC 1542 says "The IP Total Length and UDP Length
//	 * must be large enough to contain the minimal BOOTP header of 300 octets".
//	 * Thus, we retain enough padding to not go below 300 BOOTP bytes.
//	 * Some devices have filters which drop DHCP packets shorter than that.
//	 */
//	padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(packet.data.options);
//	if (padding > DHCP_SIZE - 300)
//		padding = DHCP_SIZE - 300;
//
//	packet.ip._proto = IPPROTO_UDP;
//	packet.ip.src.addr = source_nip;
//	packet.ip.dest.addr = dest_nip;
//	packet.udp.src = htons(source_port);
//	packet.udp.dest = htons(dest_port);
//	/* size, excluding IP header: */
//	packet.udp.len = htons(UDP_DHCP_SIZE - padding);
//	/* for UDP checksumming, ip.len is set to UDP packet len */
//	packet.ip._len = packet.udp.len;
//	packet.udp.chksum = inet_chksum((uint16_t *)&packet,
//			IP_UDP_DHCP_SIZE - padding);
//	/* but for sending, it is set to IP packet len */
//	packet.ip._len = htons(IP_UDP_DHCP_SIZE - padding);
//	packet.ip._v_hl = sizeof(packet.ip) >> 2;
////	packet.ip.version = IPVERSION;
////	packet.ip._ttl = IPDEFTTL;
//	packet.ip._chksum = inet_chksum((uint16_t *)&packet.ip, sizeof(packet.ip));
//
//	udhcp_dump_packet(dhcp_pkt);
////	result = sendto(fd, &packet, IP_UDP_DHCP_SIZE - padding, /*flags:*/ 0,
////			(struct sockaddr *) &dest_sll, sizeof(dest_sll));
//	msg = "sendto(%s)\n";
// ret_close:
//	close(fd);
//	if (result < 0) {
// ret_msg:
// 	 UDHCP_DEBUG(msg, "PACKET");
//	}
//	return result;
//}

/* Let the kernel do all the work for packet generation */
int ICACHE_FLASH_ATTR udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
		uint32_t source_nip, int source_port,
		uint32_t dest_nip, int dest_port)
{
	struct sockaddr_in sa;
	unsigned padding;
	int fd;
	int result = -1;
	const char *msg;

	fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if (fd < 0) {
		msg = "socket(%s)\n";
		goto ret_msg;
	}
//	setsockopt_reuseaddr(fd);

	memset(&sa, 0, sizeof(sa));
	sa.sin_family = AF_INET;
	sa.sin_port = htons(source_port);
	sa.sin_addr.s_addr = source_nip;
	if (bind(fd, (struct sockaddr *)&sa, sizeof(sa)) == -1) {
		msg = "bind(%s)\n";
		goto ret_close;
	}

	memset(&sa, 0, sizeof(sa));
	sa.sin_family = AF_INET;
	sa.sin_port = htons(dest_port);
	sa.sin_addr.s_addr = dest_nip;
	if (connect(fd, (struct sockaddr *)&sa, sizeof(sa)) == -1) {
		msg = "connect(%s)\n";
		goto ret_close;
	}

	udhcp_dump_packet(dhcp_pkt);
	padding = DHCP_OPTIONS_BUFSIZE - 1 - udhcp_end_option(dhcp_pkt->options);
	if (padding > DHCP_SIZE - 300)
		padding = DHCP_SIZE - 300;
	result = safe_write(fd, dhcp_pkt, DHCP_SIZE - padding);
	msg = "write(%s)\n";
 ret_close:
	close(fd);
	if (result < 0) {
 ret_msg:
 	 UDHCP_DEBUG(msg, "UDP");
	}
	return result;
}
